Please do not multipost.

That's the whole purpose of the classpath. Otherwise how does Java know
where to find the classes it's looking for?

When you put your classes in a JAR file, that JAR file has a manifest. You
can use the default manifest, and add two headers to it to create a
"self-contained" application:
    Main-Class: package.to.MainClass
    Class-Path: library1.jar library2.jar

The Class-Path header contains relative URL's to the JAR files. IN the
example above, it looks for the JAR files it depends on in the current
directory.

As pointed out by others, you can also place the JAR files you depend upon
in the lib/ext subdirectory of the directory the JRE resides in.
Personally, I prefer the first approach however; it's easier to uninstall
(as no other application will use your files).

Oscar